1. Field of the Invention
The present invention relates to an electrophotographic plate-making machine using a scanning exposure system and enabling a photo composing.
2. Description of the Related Art
Two type of electrophotographic plate-making machines are most widely used, i.e. a stationary exposure system and a scanning exposure system. Proposals have been made to use a stationary exposure system for carrying out photo composing i.e., grouping a plurality of pictures on a single sheet of sensitive paper (master paper) at different portions thereof from a common copy. For example, Japanese Unexamined Patent Publication No. 61-4065 discloses an electrophotographic plate making apparatus in which exposures from a light source are made twice on a sensitive paper, one exposure on the upper half of the sensitive paper and another on the lower half of the sensitive paper. In this case, an upper light shielding cover and a lower light shielding cover are provided to respectively cover the upper and lower halves of the sensitive paper. Namely, the lower half of the sensitive paper is covered by the lower light shielding cover when the upper half of the sensitive paper is to be exposed, and alternatively, the upper half of the sensitive paper is covered by the upper light shielding cover when the lower half of the sensitive paper is to be exposed.
Nevertheless, there have been no proposal for carrying out photo composing in a scanning exposure system, as it appears that arrangement of the conventional scanning exposure system makes it impossible to apply a light shielding cover of the above described type to such a scanning exposure system.